1
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Wang R, Nji Wandi B, Schwartz N, Hecht J, Ponomareva L, Paige K, West A, Desanti K, Nguyen J, Niemi J, Thorson JS, Shaaban KA, Metsä-Ketelä M, Nybo SE. Diverse Combinatorial Biosynthesis Strategies for C-H Functionalization of Anthracyclinones. ACS Synth Biol 2024; 13:1523-1536. [PMID: 38662967 PMCID: PMC11101304 DOI: 10.1021/acssynbio.4c00043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Revised: 04/11/2024] [Accepted: 04/16/2024] [Indexed: 05/18/2024]
Abstract
Streptomyces spp. are "nature's antibiotic factories" that produce valuable bioactive metabolites, such as the cytotoxic anthracycline polyketides. While the anthracyclines have hundreds of natural and chemically synthesized analogues, much of the chemical diversity stems from enzymatic modifications to the saccharide chains and, to a lesser extent, from alterations to the core scaffold. Previous work has resulted in the generation of a BioBricks synthetic biology toolbox in Streptomyces coelicolor M1152ΔmatAB that could produce aklavinone, 9-epi-aklavinone, auramycinone, and nogalamycinone. In this work, we extended the platform to generate oxidatively modified analogues via two crucial strategies. (i) We swapped the ketoreductase and first-ring cyclase enzymes for the aromatase cyclase from the mithramycin biosynthetic pathway in our polyketide synthase (PKS) cassettes to generate 2-hydroxylated analogues. (ii) Next, we engineered several multioxygenase cassettes to catalyze 11-hydroxylation, 1-hydroxylation, 10-hydroxylation, 10-decarboxylation, and 4-hydroxyl regioisomerization. We also developed improved plasmid vectors and S. coelicolor M1152ΔmatAB expression hosts to produce anthracyclinones. This work sets the stage for the combinatorial biosynthesis of bespoke anthracyclines using recombinant Streptomyces spp. hosts.
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Affiliation(s)
- Rongbin Wang
- Department
of Life Technologies, University of Turku, FIN-20014 Turku, Finland
| | - Benjamin Nji Wandi
- Department
of Life Technologies, University of Turku, FIN-20014 Turku, Finland
| | - Nora Schwartz
- Department
of Pharmaceutical Sciences, College of Pharmacy, Ferris State University, Big Rapids, Michigan 49307, United States
| | - Jacob Hecht
- Department
of Pharmaceutical Sciences, College of Pharmacy, Ferris State University, Big Rapids, Michigan 49307, United States
| | - Larissa Ponomareva
- Center
for Pharmaceutical Research and Innovation, Department of Pharmaceutical Sciences,
College of Pharmacy, University of Kentucky, Lexington, Kentucky 40536, United States
| | - Kendall Paige
- Department
of Pharmaceutical Sciences, College of Pharmacy, Ferris State University, Big Rapids, Michigan 49307, United States
| | - Alexis West
- Department
of Pharmaceutical Sciences, College of Pharmacy, Ferris State University, Big Rapids, Michigan 49307, United States
| | - Kathryn Desanti
- Department
of Pharmaceutical Sciences, College of Pharmacy, Ferris State University, Big Rapids, Michigan 49307, United States
| | - Jennifer Nguyen
- Department
of Pharmaceutical Sciences, College of Pharmacy, Ferris State University, Big Rapids, Michigan 49307, United States
| | - Jarmo Niemi
- Department
of Life Technologies, University of Turku, FIN-20014 Turku, Finland
| | - Jon S. Thorson
- Center
for Pharmaceutical Research and Innovation, Department of Pharmaceutical Sciences,
College of Pharmacy, University of Kentucky, Lexington, Kentucky 40536, United States
| | - Khaled A. Shaaban
- Center
for Pharmaceutical Research and Innovation, Department of Pharmaceutical Sciences,
College of Pharmacy, University of Kentucky, Lexington, Kentucky 40536, United States
| | - Mikko Metsä-Ketelä
- Department
of Life Technologies, University of Turku, FIN-20014 Turku, Finland
| | - S. Eric Nybo
- Department
of Pharmaceutical Sciences, College of Pharmacy, Ferris State University, Big Rapids, Michigan 49307, United States
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2
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Gui C, Kalkreuter E, Liu YC, Li G, Steele AD, Yang D, Chang C, Shen B. Cofactorless oxygenases guide anthraquinone-fused enediyne biosynthesis. Nat Chem Biol 2024; 20:243-250. [PMID: 37945897 DOI: 10.1038/s41589-023-01476-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Accepted: 10/10/2023] [Indexed: 11/12/2023]
Abstract
The anthraquinone-fused enediynes (AFEs) combine an anthraquinone moiety and a ten-membered enediyne core capable of generating a cytotoxic diradical species. AFE cyclization is triggered by opening the F-ring epoxide, which is also the site of the most structural diversity. Previous studies of tiancimycin A, a heavily modified AFE, have revealed a cryptic aldehyde blocking installation of the epoxide, and no unassigned oxidases could be predicted within the tnm biosynthetic gene cluster. Here we identify two consecutively acting cofactorless oxygenases derived from methyltransferase and α/β-hydrolase protein folds, TnmJ and TnmK2, respectively, that are responsible for F-ring tailoring in tiancimycin biosynthesis by comparative genomics. Further biochemical and structural characterizations reveal that the electron-rich AFE anthraquinone moiety assists in catalyzing deformylation, epoxidation and oxidative ring cleavage without exogenous cofactors. These enzymes therefore fill important knowledge gaps for the biosynthesis of this class of molecules and the underappreciated family of cofactorless oxygenases.
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Affiliation(s)
- Chun Gui
- Department of Chemistry, The Herbert Wertheim UF Scripps Institute for Biomedical Innovation & Technology, University of Florida, Jupiter, FL, USA
| | - Edward Kalkreuter
- Department of Chemistry, The Herbert Wertheim UF Scripps Institute for Biomedical Innovation & Technology, University of Florida, Jupiter, FL, USA
| | - Yu-Chen Liu
- Department of Chemistry, The Herbert Wertheim UF Scripps Institute for Biomedical Innovation & Technology, University of Florida, Jupiter, FL, USA
| | - Gengnan Li
- Department of Chemistry, The Herbert Wertheim UF Scripps Institute for Biomedical Innovation & Technology, University of Florida, Jupiter, FL, USA
| | - Andrew D Steele
- Department of Chemistry, The Herbert Wertheim UF Scripps Institute for Biomedical Innovation & Technology, University of Florida, Jupiter, FL, USA
| | - Dong Yang
- Department of Chemistry, The Herbert Wertheim UF Scripps Institute for Biomedical Innovation & Technology, University of Florida, Jupiter, FL, USA
- Natural Products Discovery Center, The Herbert Wertheim UF Scripps Institute for Biomedical Innovation & Technology, University of Florida, Jupiter, FL, USA
| | - Changsoo Chang
- Structural Biology Center, X-ray Science Division, Argonne National Laboratory, Lemont, IL, USA
| | - Ben Shen
- Department of Chemistry, The Herbert Wertheim UF Scripps Institute for Biomedical Innovation & Technology, University of Florida, Jupiter, FL, USA.
- Natural Products Discovery Center, The Herbert Wertheim UF Scripps Institute for Biomedical Innovation & Technology, University of Florida, Jupiter, FL, USA.
- Department of Molecular Medicine, The Herbert Wertheim UF Scripps Institute for Biomedical Innovation & Technology, University of Florida, Jupiter, FL, USA.
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3
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Pal P, Wessely SML, Townsend CA. Normal and Aberrant Methyltransferase Activities Give Insights into the Final Steps of Dynemicin A Biosynthesis. J Am Chem Soc 2023; 145:12935-12947. [PMID: 37276497 PMCID: PMC10985829 DOI: 10.1021/jacs.3c04393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The naturally occurring enediynes are notable for their complex structures, potent DNA cleaving ability, and emerging usefulness in cancer chemotherapy. They can be classified into three distinct structural families, but all are thought to originate from a common linear C15-heptaene. Dynemicin A (DYN) is the paradigm member of anthraquinone-fused enediynes, one of the three main classes and exceptional among them for derivation of both its enediyne and anthraquinone portions from this same early biosynthetic building block. Evidence is growing about how two structurally dissimilar, but biosynthetically related, intermediates combine in two heterodimerization reactions to create a nitrogen-containing C30-coupled product. We report here deletions of two genes that encode biosynthetic proteins that are annotated as S-adenosylmethionine (SAM)-dependent methyltransferases. While one, DynO6, is indeed the required O-methyltransferase implicated long ago in the first studies of DYN biosynthesis, the other, DynA5, functions in an unanticipated manner in the post-heterodimerization events that complete the biosynthesis of DYN. Despite its removal from the genome of Micromonospora chersina, the ΔdynA5 strain retains the ability to synthesize DYN, albeit in reduced titers, accompanied by two unusual co-metabolites. We link the appearance of these unexpected structures to a substantial and contradictory body of other recent experimental data to advance a biogenetic rationale for the downstream steps that lead to the final formation of DYN. A sequence of product-forming transformations that is in line with new and existing experimental results is proposed and supported by a model reaction that also encompasses the formation of the crucial epoxide essential for the activation of DYN for DNA cleavage.
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Affiliation(s)
- Paramita Pal
- Department of Chemistry, The Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States
| | - Serena M L Wessely
- Department of Chemistry, The Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States
| | - Craig A Townsend
- Department of Chemistry, The Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States
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4
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Hulst MB, Grocholski T, Neefjes JJC, van Wezel GP, Metsä-Ketelä M. Anthracyclines: biosynthesis, engineering and clinical applications. Nat Prod Rep 2021; 39:814-841. [PMID: 34951423 DOI: 10.1039/d1np00059d] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Covering: January 1995 to June 2021Anthracyclines are glycosylated microbial natural products that harbour potent antiproliferative activities. Doxorubicin has been widely used as an anticancer agent in the clinic for several decades, but its use is restricted due to severe side-effects such as cardiotoxicity. Recent studies into the mode-of-action of anthracyclines have revealed that effective cardiotoxicity-free anthracyclines can be generated by focusing on histone eviction activity, instead of canonical topoisomerase II poisoning leading to double strand breaks in DNA. These developments have coincided with an increased understanding of the biosynthesis of anthracyclines, which has allowed generation of novel compound libraries by metabolic engineering and combinatorial biosynthesis. Coupled to the continued discovery of new congeners from rare Actinobacteria, a better understanding of the biology of Streptomyces and improved production methodologies, the stage is set for the development of novel anthracyclines that can finally surpass doxorubicin at the forefront of cancer chemotherapy.
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Affiliation(s)
- Mandy B Hulst
- Institute of Biology, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands.
| | - Thadee Grocholski
- Department of Life Technologies, University of Turku, FIN-20014 Turku, Finland
| | - Jacques J C Neefjes
- Department of Cell and Chemical Biology and Oncode Institute, Leiden University Medical Centre, Leiden, The Netherlands
| | - Gilles P van Wezel
- Institute of Biology, Leiden University, Sylviusweg 72, 2333 BE Leiden, The Netherlands.
| | - Mikko Metsä-Ketelä
- Department of Life Technologies, University of Turku, FIN-20014 Turku, Finland
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5
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Cai X, Li C, Ichinose K, Jiang Y, Liu M, Wang H, Gong C, Li L, Wan J, Zhao Y, Yang Q, Li A. A single-domain small protein Med-ORF10 regulates the production of antitumour agent medermycin in Streptomyces. Microb Biotechnol 2021; 14:1918-1930. [PMID: 34139068 PMCID: PMC8449675 DOI: 10.1111/1751-7915.13834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 04/19/2021] [Accepted: 05/03/2021] [Indexed: 11/28/2022] Open
Abstract
Med-ORF10, a single-domain protein with unknown function encoded by a gene located in a gene cluster responsible for the biosynthesis of a novel antitumour antibiotic medermycin, shares high homology to a group of small proteins widely distributed in many aromatic polyketide antibiotic pathways. This group of proteins contain a nuclear transport factor-2 (NTF-2) domain and appear to undergo an evolutionary divergence in their functions. Gene knockout and interspecies complementation suggested that Med-ORF10 plays a regulatory role in medermycin biosynthetic pathway. Overexpression of med-ORF10 in its wild-type strain led to significant increase of medermycin production. It was also shown by qRT-PCR and Western blot that Med-ORF10 controls the expression of genes encoding tailoring enzymes involved in medermycin biosynthesis. Transcriptome analysis and qRT-PCR revealed that Med-ORF10 has pleiotropic effects on more targets. However, there is no similar conserved domain available in Med-ORF10 compared to those of mechanistically known regulatory proteins; meanwhile, no direct interaction between Med-ORF10 and its target promoter DNA was detected via gel shift assay. All these studies suggest that Med-ORF10 regulates medermycin biosynthesis probably via an indirect mode.
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Affiliation(s)
- Xiaofeng Cai
- Helmholtz International Lab for Anti-Infectives, Shandong University-Helmholtz Institute of Biotechnology, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237, China.,The College of Life Sciences, Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, Central China Normal University, Wuhan, 430079, China.,School of Pharmacy, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Caiyun Li
- Helmholtz International Lab for Anti-Infectives, Shandong University-Helmholtz Institute of Biotechnology, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237, China
| | - Koji Ichinose
- Research Institute of Pharmaceutical Sciences, Musashino University, Tokyo, 202-8585, Japan
| | - Yali Jiang
- The College of Life Sciences, Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, Central China Normal University, Wuhan, 430079, China
| | - Ming Liu
- The College of Life Sciences, Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, Central China Normal University, Wuhan, 430079, China
| | - Huili Wang
- The College of Life Sciences, Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, Central China Normal University, Wuhan, 430079, China
| | - Caixia Gong
- The College of Life Sciences, Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, Central China Normal University, Wuhan, 430079, China
| | - Le Li
- The College of Life Sciences, Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, Central China Normal University, Wuhan, 430079, China
| | - Juan Wan
- The College of Life Sciences, Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, Central China Normal University, Wuhan, 430079, China
| | - Yiming Zhao
- Helmholtz International Lab for Anti-Infectives, Shandong University-Helmholtz Institute of Biotechnology, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237, China
| | - Qing Yang
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Songhu Road 2005, Shanghai, 200438, China
| | - Aiying Li
- Helmholtz International Lab for Anti-Infectives, Shandong University-Helmholtz Institute of Biotechnology, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237, China.,The College of Life Sciences, Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, Central China Normal University, Wuhan, 430079, China
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6
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Sun Q, Huang M, Wei Y. Diversity of the reaction mechanisms of SAM-dependent enzymes. Acta Pharm Sin B 2021; 11:632-650. [PMID: 33777672 PMCID: PMC7982431 DOI: 10.1016/j.apsb.2020.08.011] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 07/30/2020] [Accepted: 08/08/2020] [Indexed: 02/08/2023] Open
Abstract
S-adenosylmethionine (SAM) is ubiquitous in living organisms and is of great significance in metabolism as a cofactor of various enzymes. Methyltransferases (MTases), a major group of SAM-dependent enzymes, catalyze methyl transfer from SAM to C, O, N, and S atoms in small-molecule secondary metabolites and macromolecules, including proteins and nucleic acids. MTases have long been a hot topic in biomedical research because of their crucial role in epigenetic regulation of macromolecules and biosynthesis of natural products with prolific pharmacological moieties. However, another group of SAM-dependent enzymes, sharing similar core domains with MTases, can catalyze nonmethylation reactions and have multiple functions. Herein, we mainly describe the nonmethylation reactions of SAM-dependent enzymes in biosynthesis. First, we compare the structural and mechanistic similarities and distinctions between SAM-dependent MTases and the non-methylating SAM-dependent enzymes. Second, we summarize the reactions catalyzed by these enzymes and explore the mechanisms. Finally, we discuss the structural conservation and catalytical diversity of class I-like non-methylating SAM-dependent enzymes and propose a possibility in enzymes evolution, suggesting future perspectives for enzyme-mediated chemistry and biotechnology, which will help the development of new methods for drug synthesis.
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7
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Oliveira R, Bush MJ, Pires S, Chandra G, Casas-Pastor D, Fritz G, Mendes MV. The novel ECF56 SigG1-RsfG system modulates morphological differentiation and metal-ion homeostasis in Streptomyces tsukubaensis. Sci Rep 2020; 10:21728. [PMID: 33303917 PMCID: PMC7730460 DOI: 10.1038/s41598-020-78520-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 11/26/2020] [Indexed: 12/16/2022] Open
Abstract
Extracytoplasmic function (ECF) sigma factors are key transcriptional regulators that prokaryotes have evolved to respond to environmental challenges. Streptomyces tsukubaensis harbours 42 ECFs to reprogram stress-responsive gene expression. Among them, SigG1 features a minimal conserved ECF σ2-σ4 architecture and an additional C-terminal extension that encodes a SnoaL_2 domain, which is characteristic for ECF σ factors of group ECF56. Although proteins with such domain organisation are widely found among Actinobacteria, the functional role of ECFs with a fused SnoaL_2 domain remains unknown. Our results show that in addition to predicted self-regulatory intramolecular amino acid interactions between the SnoaL_2 domain and the ECF core, SigG1 activity is controlled by the cognate anti-sigma protein RsfG, encoded by a co-transcribed sigG1-neighbouring gene. Characterisation of ∆sigG1 and ∆rsfG strains combined with RNA-seq and ChIP-seq experiments, suggests the involvement of SigG1 in the morphological differentiation programme of S. tsukubaensis. SigG1 regulates the expression of alanine dehydrogenase, ald and the WhiB-like regulator, wblC required for differentiation, in addition to iron and copper trafficking systems. Overall, our work establishes a model in which the activity of a σ factor of group ECF56, regulates morphogenesis and metal-ions homeostasis during development to ensure the timely progression of multicellular differentiation.
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Affiliation(s)
- Rute Oliveira
- Bioengineering and Synthetic Microbiology Group, i3S- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- IBMC, Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
- Programa Doutoral em Biologia Molecular e Celular (MCBiology), ICBAS, Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Matthew J Bush
- Department of Molecular Microbiology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Sílvia Pires
- IBMC, Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
- Jill Roberts Institute for IBD Research, Weill Cornell Medicine, New York, NY, 10021, USA
| | - Govind Chandra
- Department of Molecular Microbiology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Delia Casas-Pastor
- Center for Synthetic Microbiology, Philipps-University Marburg, 35032, Marburg, Germany
| | - Georg Fritz
- School for Molecular Sciences, University of Western Australia, Perth, 6009, Australia
| | - Marta V Mendes
- Bioengineering and Synthetic Microbiology Group, i3S- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.
- IBMC, Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal.
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8
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Nji Wandi B, Siitonen V, Palmu K, Metsä-Ketelä M. The Rieske Oxygenase SnoT Catalyzes 2''-Hydroxylation of l-Rhodosamine in Nogalamycin Biosynthesis. Chembiochem 2020; 21:3062-3066. [PMID: 32557994 DOI: 10.1002/cbic.202000229] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 06/11/2020] [Indexed: 02/02/2023]
Abstract
Nogalamycin is an anthracycline anti-cancer agent that intercalates into the DNA double helix. The binding is facilitated by two carbohydrate units, l-nogalose and l-nogalamine, that interact with the minor and major grooves of DNA, respectively. However, recent investigations have shown that nogalamycin biosynthesis proceeds through the attachment of l-rhodosamine (2''-deoxy-4''-epi-l-nogalamine) to the aglycone. Herein, we demonstrate that the Rieske enzyme SnoT catalyzes 2''-hydroxylation of l-rhodosamine as an initial post-glycosylation step. Furthermore, we establish that the reaction order continues with 2-5'' carbocyclization and 4'' epimerization by the non-heme iron and 2-oxoglutarate-dependent enzymes SnoK and SnoN, respectively. These late-stage tailoring steps are important for the bioactivity of nogalamycin due to involvement of the 2''- and 4''-hydroxy groups of l-nogalamine in hydrogen bonding interactions with DNA.
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Affiliation(s)
- Benjamin Nji Wandi
- Department of Biochemistry, University of Turku, Vatselankatu, 2, 20014, Turku, Finland
| | - Vilja Siitonen
- Department of Biochemistry, University of Turku, Vatselankatu, 2, 20014, Turku, Finland
| | - Kaisa Palmu
- Department of Biochemistry, University of Turku, Vatselankatu, 2, 20014, Turku, Finland
| | - Mikko Metsä-Ketelä
- Department of Biochemistry, University of Turku, Vatselankatu, 2, 20014, Turku, Finland
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9
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Vuksanovic N, Zhu X, Serrano DA, Siitonen V, Metsä-Ketelä M, Melançon CE, Silvaggi NR. Structural characterization of three noncanonical NTF2-like superfamily proteins: implications for polyketide biosynthesis. Acta Crystallogr F Struct Biol Commun 2020; 76:372-383. [PMID: 32744249 PMCID: PMC7397469 DOI: 10.1107/s2053230x20009814] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Accepted: 07/17/2020] [Indexed: 12/12/2022] Open
Abstract
Proteins belonging to the NTF2-like superfamily are present in the biosynthetic pathways of numerous polyketide natural products, such as anthracyclins and benzoisochromanequinones. Some have been found to be bona fide polyketide cyclases, but many of them have roles that are currently unknown. Here, the X-ray crystal structures of three NTF2-like proteins of unknown function are reported: those of ActVI-ORFA from Streptomyces coelicolor A3(2) and its homologs Caci_6494, a protein from an uncharacterized biosynthetic cluster in Catenulispora acidiphila, and Aln2 from Streptomyces sp. CM020, a protein in the biosynthetic pathway of alnumycin. The presence of a solvent-accessible cavity and the conservation of the His/Asp dyad that is characteristic of many polyketide cyclases suggest a potential enzymatic role for these enzymes in polyketide biosynthesis.
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Affiliation(s)
- Nemanja Vuksanovic
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, 3210 North Cramer Street, Milwaukee, WI 53211, USA
| | - Xuechen Zhu
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, NM 87131-0001, USA
| | - Dante A. Serrano
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, 3210 North Cramer Street, Milwaukee, WI 53211, USA
| | - Vilja Siitonen
- Department of Biochemistry, University of Turku, FIN-20014 Turku, Finland
| | - Mikko Metsä-Ketelä
- Department of Biochemistry, University of Turku, FIN-20014 Turku, Finland
| | - Charles E. Melançon
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, NM 87131-0001, USA
| | - Nicholas R. Silvaggi
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, 3210 North Cramer Street, Milwaukee, WI 53211, USA
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10
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Nji Wandi B, Siitonen V, Dinis P, Vukic V, Salminen TA, Metsä-Ketelä M. Evolution-guided engineering of non-heme iron enzymes involved in nogalamycin biosynthesis. FEBS J 2020; 287:2998-3011. [PMID: 31876382 DOI: 10.1111/febs.15192] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 11/20/2019] [Accepted: 12/20/2019] [Indexed: 01/05/2023]
Abstract
Microbes are competent chemists that are able to generate thousands of chemically complex natural products with potent biological activities. The key to the formation of this chemical diversity has been the rapid evolution of secondary metabolism. Many enzymes residing on these metabolic pathways have acquired atypical catalytic properties in comparison with their counterparts found in primary metabolism. The biosynthetic pathway of the anthracycline nogalamycin contains two such proteins, SnoK and SnoN, belonging to nonheme iron and 2-oxoglutarate-dependent mono-oxygenases. In spite of structural similarity, the two proteins catalyze distinct chemical reactions; SnoK is a C2-C5″ carbocyclase, whereas SnoN catalyzes stereoinversion at the adjacent C4″ position. Here, we have identified four structural regions involved in the functional differentiation and generated 30 chimeric enzymes to probe catalysis. Our analyses indicate that the carbocyclase SnoK is the ancestral form of the enzyme from which SnoN has evolved to catalyze stereoinversion at the neighboring carbon. The critical step in the appearance of epimerization activity has likely been the insertion of three residues near the C-terminus, which allow repositioning of the substrate in front of the iron center. The loss of the original carbocyclization activity has then occurred with changes in four amino acids near the iron center that prohibit alignment of the substrate for the formation of the C2-C5″ bond. Our study provides detailed insights into the evolutionary processes that have enabled Streptomyces soil bacteria to become the major source of antibiotics and antiproliferative agents. ENZYMES: EC number 1.14.11.
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Affiliation(s)
| | - Vilja Siitonen
- Department of Biochemistry, University of Turku, Finland
| | - Pedro Dinis
- Department of Biochemistry, University of Turku, Finland
| | - Vladimir Vukic
- Structural Bioinformatics Laboratory, Biochemistry, Faculty of Science and Engineering, Åbo Akademi University, Turku, Finland.,Faculty of Technology Novi Sad, University of Novi Sad, Serbia
| | - Tiina A Salminen
- Structural Bioinformatics Laboratory, Biochemistry, Faculty of Science and Engineering, Åbo Akademi University, Turku, Finland
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11
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Li H, Zhu W, Liu Y. Mechanism of Uncoupled Carbocyclization and Epimerization Catalyzed by Two Non-Heme Iron/α-Ketoglutarate Dependent Enzymes. J Chem Inf Model 2019; 59:5086-5098. [PMID: 31790238 DOI: 10.1021/acs.jcim.9b00837] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The non-heme iron/α-ketoglutarate dependent enzymes SnoK and SnoN from Streptomyces nogalater are involved in the biosynthesis of anthracycline nogalamycin. Although they have similar active sites, SnoK is responsible for carbocyclization whereas SnoN solely catalyzes the hydroxyl epimerization. Herein, we performed docking, molecular simulations, and a series of combined quantum mechanics and molecular mechanics (QM/MM) calculations to illuminate the mechanisms of two enzymes. The catalytic reactions of two enzymes occur on the quintet state surface. For SnoK, the whole reaction includes two separated hydrogen-abstraction steps and one radical addition, and the latter step is calculated to be rate limiting with an energy barrier of 21.7 kcal/mol. Residue D106 is confirmed to participate in the construction of the hydrogen bond network, which plays a crucial role in positioning the bulky substrate in a specific orientation. Moreover, it is found that SnoN is only responsible for the hydrogen abstraction of the intermediate, and no residue was suggested to be suitable for donating a hydrogen atom to the substrate radical, which further confirms the suggestion based on experiments that either a cellular reductant or another enzyme protein could donate a hydrogen atom to the substrate. Our docking results coincide with the previous structural study that the different roles of two enzymes are achieved by minor changes in the alignment of the substrates in front of the reactive ferryl-oxo species. This work highlights the reaction mechanisms catalyzed by SnoK and SnoN, which is helpful for engineering the enzymes for the biosynthesis of anthracycline nogalamycin.
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Affiliation(s)
- Hong Li
- Key Lab of Colloid and Interface Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering , Shandong University , Jinan , Shandong 250100 , China
| | - Wenyou Zhu
- College of Chemistry and Chemical Engineering , Xuzhou Institute of Technology , Xuzhou , Jiangsu 221111 , China
| | - Yongjun Liu
- Key Lab of Colloid and Interface Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering , Shandong University , Jinan , Shandong 250100 , China
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12
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Fewer DP, Metsä‐Ketelä M. A pharmaceutical model for the molecular evolution of microbial natural products. FEBS J 2019; 287:1429-1449. [DOI: 10.1111/febs.15129] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 10/11/2019] [Accepted: 11/05/2019] [Indexed: 12/20/2022]
Affiliation(s)
- David P. Fewer
- Department of Microbiology University of Helsinki Finland
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13
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Song H, Naowarojna N, Cheng R, Lopez J, Liu P. Non-heme iron enzyme-catalyzed complex transformations: Endoperoxidation, cyclopropanation, orthoester, oxidative C-C and C-S bond formation reactions in natural product biosynthesis. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2019; 117:1-61. [PMID: 31564305 DOI: 10.1016/bs.apcsb.2019.06.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Non-heme iron enzymes catalyze a wide range of chemical transformations, serving as one of the key types of tailoring enzymes in the biosynthesis of natural products. Hydroxylation reaction is the most common type of reactions catalyzed by these enzymes and hydroxylation reactions have been extensively investigated mechanistically. However, the mechanistic details for other types of transformations remain largely unknown or unexplored. In this paper, we present some of the most recently discovered transformations, including endoperoxidation, orthoester formation, cyclopropanation, oxidative C-C and C-S bond formation reactions. In addition, many of them are multi-functional enzymes, which further complicate their mechanistic investigations. In this work, we summarize their biosynthetic pathways, with special emphasis on the mechanistic details available for these newly discovered enzymes.
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Affiliation(s)
- Heng Song
- College of Chemistry and Molecular Sciences, Wuhan University, Hubei, People's Republic of China
| | | | - Ronghai Cheng
- Department of Chemistry, Boston University, Boston, MA, United States
| | - Juan Lopez
- Department of Chemistry, Boston University, Boston, MA, United States
| | - Pinghua Liu
- Department of Chemistry, Boston University, Boston, MA, United States
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14
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Grocholski T, Yamada K, Sinkkonen J, Tirkkonen H, Niemi J, Metsä-Ketelä M. Evolutionary Trajectories for the Functional Diversification of Anthracycline Methyltransferases. ACS Chem Biol 2019; 14:850-856. [PMID: 30995392 PMCID: PMC6750894 DOI: 10.1021/acschembio.9b00238] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
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Microbial natural
products are an important source of chemical
entities for drug discovery. Recent advances in understanding the
biosynthesis of secondary metabolites has revealed how this rich chemical
diversity is generated through functional differentiation of biosynthetic
enzymes. For instance, investigations into anthracycline anticancer
agents have uncovered distinct S-adenosyl methionine (SAM)-dependent
proteins: DnrK is a 4-O-methyltransferase involved in daunorubicin
biosynthesis, whereas RdmB (52% sequence identity) from the rhodomycin
pathway catalyzes 10-hydroxylation. Here, we have mined unknown anthracycline
gene clusters and discovered a third protein subclass catalyzing 10-decarboxylation.
Subsequent isolation of komodoquinone B from two Streptomyces strains verified the biological relevance of the decarboxylation
activity. Phylogenetic analysis inferred two independent routes for
the conversion of methyltransferases into hydroxylases, with a two-step
process involving loss-of-methylation and gain-of-hydroxylation presented
here. Finally, we show that simultaneously with the functional differentiation,
the evolutionary process has led to alterations in substrate specificities.
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15
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Affiliation(s)
- Cheng Feng
- College of Pharmaceutical Sciences, Southwest University, Chongqing 400715, P. R. China
| | - Qian Wei
- College of Pharmaceutical Sciences, Southwest University, Chongqing 400715, P. R. China
| | - Changhua Hu
- College of Pharmaceutical Sciences, Southwest University, Chongqing 400715, P. R. China
| | - Yi Zou
- College of Pharmaceutical Sciences, Southwest University, Chongqing 400715, P. R. China
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16
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Cantú Reinhard FG, DuBois JL, de Visser SP. Catalytic Mechanism of Nogalamycin Monoxygenase: How Does Nature Synthesize Antibiotics without a Metal Cofactor? J Phys Chem B 2018; 122:10841-10854. [DOI: 10.1021/acs.jpcb.8b09648] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Fabián G. Cantú Reinhard
- Manchester Institute of Biotechnology and School of Chemical Engineering and Analytical Science, The University of Manchester, 131 Princess Street, Manchester M1 7DN, U.K
| | - Jennifer L. DuBois
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59715-3400, United States
| | - Sam P. de Visser
- Manchester Institute of Biotechnology and School of Chemical Engineering and Analytical Science, The University of Manchester, 131 Princess Street, Manchester M1 7DN, U.K
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Bacterial Enzymes Catalyzing the Synthesis of 1,8-Dihydroxynaphthalene, a Key Precursor of Dihydroxynaphthalene Melanin, from Sorangium cellulosum. Appl Environ Microbiol 2018; 84:AEM.00258-18. [PMID: 29500263 DOI: 10.1128/aem.00258-18] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 02/21/2018] [Indexed: 12/27/2022] Open
Abstract
1,8-Dihydroxynaphthalene (1,8-DHN) is a key intermediate in the biosynthesis of DHN melanin, which is specific to fungi. In this study, we characterized the enzymatic properties of the gene products of an operon consisting of soceCHS1, bdsA, and bdsB from the Gram-negative bacterium Sorangium cellulosum Heterologous expression of soceCHS1, bdsA, and bdsB in Streptomyces coelicolor caused secretion of a dark-brown pigment into the broth. High-performance liquid chromatography (HPLC) analysis of the broth revealed that the recombinant strain produced 1,8-DHN, indicating that the operon encoded a novel enzymatic system for the synthesis of 1,8-DHN. Simultaneous incubation of the recombinant SoceCHS1, BdsA, and BdsB with malonyl-coenzyme A (malonyl-CoA) and NADPH resulted in the synthesis of 1,8-DHN. SoceCHS1, a type III polyketide synthase (PKS), catalyzed the synthesis of 1,3,6,8-tetrahydroxynaphthalene (T4HN) in vitro T4HN was in turn converted to 1,8-DHN by successive steps of reduction and dehydration, which were catalyzed by BdsA and BdsB. BdsA, which is a member of the aldo-keto reductase (AKR) superfamily, catalyzed the reduction of T4HN and 1,3,8-tetrahydroxynaphthalene (T3HN) to scytalone and vermelone, respectively. The stereoselectivity of T4HN reduction by BdsA occurred on the si-face to give (R)-scytalone with more than 99% optical purity. BdsB, a SnoaL2-like protein, catalyzed the dehydration of scytalone and vermelone to T3HN and 1,8-DHN, respectively. The fungal pathway for the synthesis of 1,8-DHN is composed of a type I PKS, naphthol reductases of the short-chain dehydrogenase/reductase (SDR) superfamily, and scytalone dehydratase (SD). These findings demonstrated 1,8-DHN synthesis by novel enzymes of bacterial origin.IMPORTANCE Although the DHN biosynthetic pathway was thought to be specific to fungi, we discovered novel DHN synthesis enzymes of bacterial origin. The biosynthesis of bacterial DHN utilized a type III PKS for polyketide synthesis, an AKR superfamily for reduction, and a SnoaL2-like NTF2 superfamily for dehydration, whereas the biosynthesis of fungal DHN utilized a type I PKS, SDR superfamily enzyme, and SD-like NTF2 superfamily. Surprisingly, the enzyme systems comprising the pathway were significantly different from each other, suggesting independent, parallel evolution leading to the same biosynthesis. DHN melanin plays roles in host invasion and adaptation to stress in pathogenic fungi and is therefore important to study. However, it is unclear whether DHN biosynthesis occurs in bacteria. Importantly, we did find that bacterial DHN biosynthetic enzymes were conserved among pathogenic bacteria.
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18
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Adnani N, Chevrette MG, Adibhatla SN, Zhang F, Yu Q, Braun DR, Nelson J, Simpkins SW, McDonald BR, Myers CL, Piotrowski JS, Thompson CJ, Currie CR, Li L, Rajski SR, Bugni TS. Coculture of Marine Invertebrate-Associated Bacteria and Interdisciplinary Technologies Enable Biosynthesis and Discovery of a New Antibiotic, Keyicin. ACS Chem Biol 2017; 12:3093-3102. [PMID: 29121465 DOI: 10.1021/acschembio.7b00688] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Advances in genomics and metabolomics have made clear in recent years that microbial biosynthetic capacities on Earth far exceed previous expectations. This is attributable, in part, to the realization that most microbial natural product (NP) producers harbor biosynthetic machineries not readily amenable to classical laboratory fermentation conditions. Such "cryptic" or dormant biosynthetic gene clusters (BGCs) encode for a vast assortment of potentially new antibiotics and, as such, have become extremely attractive targets for activation under controlled laboratory conditions. We report here that coculturing of a Rhodococcus sp. and a Micromonospora sp. affords keyicin, a new and otherwise unattainable bis-nitroglycosylated anthracycline whose mechanism of action (MOA) appears to deviate from those of other anthracyclines. The structure of keyicin was elucidated using high resolution MS and NMR technologies, as well as detailed molecular modeling studies. Sequencing of the keyicin BGC (within the Micromonospora genome) enabled both structural and genomic comparisons to other anthracycline-producing systems informing efforts to characterize keyicin. The new NP was found to be selectively active against Gram-positive bacteria including both Rhodococcus sp. and Mycobacterium sp. E. coli-based chemical genomics studies revealed that keyicin's MOA, in contrast to many other anthracyclines, does not invoke nucleic acid damage.
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Affiliation(s)
- Navid Adnani
- Pharmaceutical
Sciences Division, School of Pharmacy, University of Wisconsin, Madison, Wisconsin 53705, United States
| | - Marc G. Chevrette
- Department
of Bacteriology, University of Wisconsin, Madison, Wisconsin 53705, United States
- Department
of Genetics, University of Wisconsin, Madison, Wisconsin 53705, United States
| | - Srikar N. Adibhatla
- Pharmaceutical
Sciences Division, School of Pharmacy, University of Wisconsin, Madison, Wisconsin 53705, United States
| | - Fan Zhang
- Pharmaceutical
Sciences Division, School of Pharmacy, University of Wisconsin, Madison, Wisconsin 53705, United States
| | - Qing Yu
- Pharmaceutical
Sciences Division, School of Pharmacy, University of Wisconsin, Madison, Wisconsin 53705, United States
| | - Doug R. Braun
- Pharmaceutical
Sciences Division, School of Pharmacy, University of Wisconsin, Madison, Wisconsin 53705, United States
| | - Justin Nelson
- Bioinformatics
and Computational Biology Program, University of Minnesota-Twin Cities, Minneapolis, Minnesota 55455, United States
| | - Scott W. Simpkins
- Bioinformatics
and Computational Biology Program, University of Minnesota-Twin Cities, Minneapolis, Minnesota 55455, United States
| | - Bradon R. McDonald
- Department
of Bacteriology, University of Wisconsin, Madison, Wisconsin 53705, United States
| | - Chad L. Myers
- Bioinformatics
and Computational Biology Program, University of Minnesota-Twin Cities, Minneapolis, Minnesota 55455, United States
- Department
of Computer Science and Engineering, University of Minnesota-Twin Cities, Minneapolis, Minnesota 55455, United States
| | | | | | - Cameron R. Currie
- Department
of Bacteriology, University of Wisconsin, Madison, Wisconsin 53705, United States
| | - Lingjun Li
- Pharmaceutical
Sciences Division, School of Pharmacy, University of Wisconsin, Madison, Wisconsin 53705, United States
| | - Scott R. Rajski
- Pharmaceutical
Sciences Division, School of Pharmacy, University of Wisconsin, Madison, Wisconsin 53705, United States
| | - Tim S. Bugni
- Pharmaceutical
Sciences Division, School of Pharmacy, University of Wisconsin, Madison, Wisconsin 53705, United States
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19
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Fungal Cordycepin Biosynthesis Is Coupled with the Production of the Safeguard Molecule Pentostatin. Cell Chem Biol 2017; 24:1479-1489.e4. [DOI: 10.1016/j.chembiol.2017.09.001] [Citation(s) in RCA: 97] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Revised: 05/05/2017] [Accepted: 09/01/2017] [Indexed: 12/31/2022]
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20
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Hydroxyl regioisomerization of anthracycline catalyzed by a four-enzyme cascade. Proc Natl Acad Sci U S A 2017; 114:1554-1559. [PMID: 28137838 DOI: 10.1073/pnas.1610097114] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Ranking among the most effective anticancer drugs, anthracyclines represent an important family of aromatic polyketides generated by type II polyketide synthases (PKSs). After formation of polyketide cores, the post-PKS tailoring modifications endow the scaffold with various structural diversities and biological activities. Here we demonstrate an unprecedented four-enzyme-participated hydroxyl regioisomerization process involved in the biosynthesis of kosinostatin. First, KstA15 and KstA16 function together to catalyze a cryptic hydroxylation of the 4-hydroxyl-anthraquinone core, yielding a 1,4-dihydroxyl product, which undergoes a chemically challenging asymmetric reduction-dearomatization subsequently acted by KstA11; then, KstA10 catalyzes a region-specific reduction concomitant with dehydration to afford the 1-hydroxyl anthraquinone. Remarkably, the shunt product identifications of both hydroxylation and reduction-dehydration reactions, the crystal structure of KstA11 with bound substrate and cofactor, and isotope incorporation experiments reveal mechanistic insights into the redox dearomatization and rearomatization steps. These findings provide a distinguished tailoring paradigm for type II PKS engineering.
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21
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Metsä-Ketelä M. Evolution inspired engineering of antibiotic biosynthesis enzymes. Org Biomol Chem 2017; 15:4036-4041. [DOI: 10.1039/c7ob00189d] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Chimeragenesis is an effective tool to probe the structure/function relationships of proteins without high-throughput screening systems. Here the proof-of-principle is presented with three pairs of proteins.
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22
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Abstract
Nogalamycin, an aromatic polyketide displaying high cytotoxicity, has a unique structure, with one of the carbohydrate units covalently attached to the aglycone via an additional carbon-carbon bond. The underlying chemistry, which implies a particularly challenging reaction requiring activation of an aliphatic carbon atom, has remained enigmatic. Here, we show that the unusual C5''-C2 carbocyclization is catalyzed by the non-heme iron α-ketoglutarate (α-KG)-dependent SnoK in the biosynthesis of the anthracycline nogalamycin. The data are consistent with a mechanistic proposal whereby the Fe(IV) = O center abstracts the H5'' atom from the amino sugar of the substrate, with subsequent attack of the aromatic C2 carbon on the radical center. We further show that, in the same metabolic pathway, the homologous SnoN (38% sequence identity) catalyzes an epimerization step at the adjacent C4'' carbon, most likely via a radical mechanism involving the Fe(IV) = O center. SnoK and SnoN have surprisingly similar active site architectures considering the markedly different chemistries catalyzed by the enzymes. Structural studies reveal that the differences are achieved by minor changes in the alignment of the substrates in front of the reactive ferryl-oxo species. Our findings significantly expand the repertoire of reactions reported for this important protein family and provide an illustrative example of enzyme evolution.
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23
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Grocholski T, Dinis P, Niiranen L, Niemi J, Metsä-Ketelä M. Divergent evolution of an atypical S-adenosyl-l-methionine-dependent monooxygenase involved in anthracycline biosynthesis. Proc Natl Acad Sci U S A 2015; 112:9866-71. [PMID: 26216966 PMCID: PMC4538628 DOI: 10.1073/pnas.1501765112] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Bacterial secondary metabolic pathways are responsible for the biosynthesis of thousands of bioactive natural products. Many enzymes residing in these pathways have evolved to catalyze unusual chemical transformations, which is facilitated by an evolutionary pressure promoting chemical diversity. Such divergent enzyme evolution has been observed in S-adenosyl-L-methionine (SAM)-dependent methyltransferases involved in the biosynthesis of anthracycline anticancer antibiotics; whereas DnrK from the daunorubicin pathway is a canonical 4-O-methyltransferase, the closely related RdmB (52% sequence identity) from the rhodomycin pathways is an atypical 10-hydroxylase that requires SAM, a thiol reducing agent, and molecular oxygen for activity. Here, we have used extensive chimeragenesis to gain insight into the functional differentiation of RdmB and show that insertion of a single serine residue to DnrK is sufficient for introduction of the monooxygenation activity. The crystal structure of DnrK-Ser in complex with aclacinomycin T and S-adenosyl-L-homocysteine refined to 1.9-Å resolution revealed that the inserted serine S297 resides in an α-helical segment adjacent to the substrate, but in a manner where the side chain points away from the active site. Further experimental work indicated that the shift in activity is mediated by rotation of a preceding phenylalanine F296 toward the active site, which blocks a channel to the surface of the protein that is present in native DnrK. The channel is also closed in RdmB and may be important for monooxygenation in a solvent-free environment. Finally, we postulate that the hydroxylation ability of RdmB originates from a previously undetected 10-decarboxylation activity of DnrK.
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Affiliation(s)
- Thadée Grocholski
- Department of Biochemistry, University of Turku, FIN-20014 Turku, Finland
| | - Pedro Dinis
- Department of Biochemistry, University of Turku, FIN-20014 Turku, Finland
| | - Laila Niiranen
- Department of Biochemistry, University of Turku, FIN-20014 Turku, Finland
| | - Jarmo Niemi
- Department of Biochemistry, University of Turku, FIN-20014 Turku, Finland
| | - Mikko Metsä-Ketelä
- Department of Biochemistry, University of Turku, FIN-20014 Turku, Finland
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Abstract
In this issue of Chemistry & Biology, Thierbach and colleagues establish the chemical mechanism for a cofactor-independent dioxygenase enzyme, a member of a small group of enzymes that can activate dioxygen without requiring a metal ion or redox cofactor.
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Affiliation(s)
- Timothy D H Bugg
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, UK.
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25
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Ma HM, Zhou Q, Tang YM, Zhang Z, Chen YS, He HY, Pan HX, Tang MC, Gao JF, Zhao SY, Igarashi Y, Tang GL. Unconventional origin and hybrid system for construction of pyrrolopyrrole moiety in kosinostatin biosynthesis. ACTA ACUST UNITED AC 2014; 20:796-805. [PMID: 23790490 DOI: 10.1016/j.chembiol.2013.04.013] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Revised: 04/22/2013] [Accepted: 04/24/2013] [Indexed: 12/14/2022]
Abstract
Kosinostatin (KST), an antitumor antibiotic, features a pyrrolopyrrole moiety spirally jointed to a five-membered ring of an anthraquinone framework glycosylated with a γ-branched octose. By a combination of in silico analysis, genetic characterization, biochemical assay, and precursor feeding experiments, a biosynthetic pathway for KST was proposed, which revealed (1) the pyrrolopyrrole moiety originates from nicotinic acid and ribose, (2) the bicyclic amidine is constructed by a process similar to the tryptophan biosynthetic pathway, and (3) a discrete adenylation enzyme and a peptidyl carrier protein (PCP) are responsible for producing a PCP-tethered building block parallel to type II polyketide synthase (PKS) rather than for the PKS priming step by providing the starter unit. These findings provide an opportunity to further explore the inexplicable enzymatic logic that governs the formation of pyrrolopyrrole moiety and the spirocyclic skeleton.
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Affiliation(s)
- Hong-Min Ma
- State Key Laboratory of Bio-organic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
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Thierbach S, Bui N, Zapp J, Chhabra SR, Kappl R, Fetzner S. Substrate-assisted O2 activation in a cofactor-independent dioxygenase. ACTA ACUST UNITED AC 2014; 21:217-25. [PMID: 24388758 DOI: 10.1016/j.chembiol.2013.11.013] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Revised: 11/22/2013] [Accepted: 11/27/2013] [Indexed: 11/29/2022]
Abstract
In contrast to the majority of O2-activating enzymes, which depend on an organic cofactor or a metal ion for catalysis, a particular group of structurally unrelated oxygenases is functional without any cofactor. In this study, we characterized the mechanism of O2 activation in the reaction pathway of a cofactor-independent dioxygenase with an α/β-hydrolase fold, which catalyzes the oxygenolytic cleavage of 2-alkyl-3-hydroxy-4(1H)-quinolones. Chemical analysis and electron paramagnetic resonance spectroscopic data revealed that O2 activation in the enzyme's active site is substrate-assisted, relying on single electron transfer from the bound substrate anion to O2 to form a radical pair, which recombines to a C2-peroxide intermediate. Thus, an oxygenase can function without a cofactor, if the organic substrate itself, after activation to a (carb)anion by an active-site base, is intrinsically reactive toward molecular oxygen.
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Affiliation(s)
- Sven Thierbach
- Institute of Molecular Microbiology and Biotechnology, University of Münster, Corrensstrasse 3, 48149 Münster, Germany
| | - Nguyen Bui
- Department of Biophysics, School of Medicine, Saarland University, Clinical Center, Building 76, 66421 Homburg, Germany
| | - Josef Zapp
- Pharmaceutical Biology, Saarland University, Campus, Building C2, 66123 Saarbrücken, Germany
| | - Siri Ram Chhabra
- School of Life Sciences, Centre for Biomolecular Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - Reinhard Kappl
- Department of Biophysics, School of Medicine, Saarland University, Clinical Center, Building 76, 66421 Homburg, Germany
| | - Susanne Fetzner
- Institute of Molecular Microbiology and Biotechnology, University of Münster, Corrensstrasse 3, 48149 Münster, Germany.
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27
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Kallio P, Patrikainen P, Belogurov GA, Mäntsälä P, Yang K, Niemi J, Metsä-Ketelä M. Tracing the evolution of angucyclinone monooxygenases: structural determinants for C-12b hydroxylation and substrate inhibition in PgaE. Biochemistry 2013; 52:4507-16. [PMID: 23731237 DOI: 10.1021/bi400381s] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Two functionally distinct homologous flavoprotein hydroxylases, PgaE and JadH, have been identified as branching points in the biosynthesis of the polyketide antibiotics gaudimycin C and jadomycin A, respectively. These evolutionarily related enzymes are both bifunctional and able to catalyze the same initial reaction, C-12 hydroxylation of the common angucyclinone intermediate prejadomycin. The enzymes diverge in their secondary activities, which include hydroxylation at C-12b by PgaE and dehydration at C-4a/C-12b by JadH. A further difference is that the C-12 hydroxylation is subject to substrate inhibition only in PgaE. Here we have identified regions associated with the C-12b hydroxylation in PgaE by extensive chimeragenesis, focusing on regions surrounding the active site. The results highlight the importance of a hairpin-β motif near the dimer interface, with two nonconserved residues, P78 and I79 (corresponding to Q89 and F90, respectively, in JadH), and invariant residue H73 playing key roles. Kinetic characterization of PgaE variants demonstrates that the secondary C-12b hydroxylation and substrate inhibition by prejadomycin are likely to be interlinked. The crystal structure of the PgaE P78Q/I79F variant at 2.4 Å resolution confirms that the changes do not alter the conformation of the β-strand secondary structure and that the side chains of these residues in effect point away from the active site toward the dimer interface. The results support a catalytic model for PgaE containing two binding modes for C-12 and C-12b hydroxylations, where binding of prejadomycin in the orientation for C-12b hydroxylation leads to substrate inhibition. The presence of an allosteric network is evident based on enzyme kinetics.
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Affiliation(s)
- Pauli Kallio
- Department of Biochemistry and Food Chemistry, University of Turku, FIN-20014 Turku, Finland
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